222 BULLETIN NO. 62. 



color. It is not clear just where the eggs are laid on corn. In 

 opening ears in the Yellowstone Valley it was noticed that while 

 some of the larvae were nearly full grown, some were still very 

 small. It was further observed that some large larvae were to be 

 found in ears that appeared to be too little eaten to had to a cun- 

 clusion that the whole life of the larvae had been in tlie ear. 



It seems probable that while the majority of the larvae as soon 

 as hatched, begin feeding on the ears, others first feed from the 

 leaves. It is most probable that most of the eggs were laid on or 

 near the ears but some eggs may have been laid on the leaves. 



The caterpillars enter the ears by way of the mass of parallel 

 strands of silk at the apex of the ear. Some very small individuals 

 were taken feeding still on the silk. From the silk they apparently 

 pass gradually to the corn at the end of the ear, and gradually they 

 woik (Unvn, seldom, however, reaching the base of the car except in 

 ears occupif d by several specimens. In leaving the ear the full-grown 

 caterpillar eats a hole through the husk leaving a conspicuous dark 

 opening. 



The castings of the caterpillars together with the moisture 

 and damaged corn within the husk, make a very unsightly mass and 

 even slightly affected ears of sweet corn become unsalable for table 

 use. In field corn the parts of afifected ears that are not eaten by 

 the caterpillars mature and harden up ready for harvesting, and the 

 damage is therefore less serious in mild cases. 



The full-fed larva enters the earth for pupation and there con- 

 structs a cell in the soil within which the caterpillar skin is molted 

 off, leaving the insect in the pupa stage. In this stage the winter 

 is passed and from the earthen cell the moth emerges the following 

 spring. In the extreme southern part of the United States some 

 five broods are produced, three of them feeding in corn. In Montana 

 there are probably two broods. 



REMEDIES. 



In other sections of the country it has been found that this in- 

 sect may be prevented from becoming very injurious to corn by hand 

 ])icking the first brood which appears before the ears are fornied. 

 Vv'hiie hand picking is a laborious practice, counting the lesults 

 which may be obtained, it seems to be advisable in fields of limited 



